Every words stands for unique digit that makes the arithmetic equation true

SEVEN + SEVEN + SIX = TWENTY.

What are the digits ?

Find the Next Number in the Sequence

2 9 3 1 8 4 3 6 5 7 ?

Queen Elizabeth organised a royal party.

To Avoid uninvited guest royal family set a password.
Jack (an uninvited person) plan to enter the party. He stand nearby the door.

First guest comes, the security person said 'twelve' and guest replied with six.
Second guest comes , the security person said 'six' and guest replied with 'three'.

Jack thought is enough and he walked to the entry point. The security person said 'eight' , Jack replied smilingly 'four'.
He was immediately thrown out of the party. why ?

What can go up a chimney down, but can’t go down a chimney up?

Can you tell a 3D object that has just two surfaces?

My first is in chocolate but not in ham. My second is in cake and also in jam. My third at tea time is easily found. Altogether, this is a friend who is often around. What is it?

What has many keys but can’t open a single lock?

I am a white box having no key or lid.
Yet there is a golden treasure inside it.

What Am I?

What 5-letter word typed in all capital letters can be read the same upside down?

1. What does:
TIM JOB
represent?

2. What does:
MO_ _
represent?